Percolation transition in the porous structure of latex-templated silica monoliths

Porous sol–gel silica monoliths are prepared using PMMA nanoparticles, 60 nm in diameter, as sacrificial templates. The pore-structure of the calcined pellets is investigated through nitrogen adsorption to assess the evolution of the porosity when varying the amount of porogen. The latex templated monoliths present a well defined spherical extrinsic porosity and an intrinsic microporosity due to preparation process. As a result of a careful analysis of the adsorption hysteresis, we identify a percolation threshold of the spherical porosity around 30% volume fraction. This phenomenon, similar to the percolation previously observed in latex-templated silica films, opens the way to the use of latex-templated porous silica monoliths with a tailorable and reliable pore structure.

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► Porous silica sol-gel monoliths are prepared using PMMA nanoparticles as sacrificial templates.
► Materials present a well defined pore structure with a straightforward pore volume adjustment.
► We identify a percolation threshold of the spherical porosity around 30% volume fraction.
► The porous structure is close to one of analog films opening the way to combined characterizations.